1. Field of the Invention
The subject matter of this invention relates generally to indicating means for submersible fuses and relates more specifically to capacitively coupled indicating means for submersible fuses.
2. Description of the Prior Art
It is known to use indicating means in conjunction with fuses. A directly connected indicator is taught in U.S. Pat. No. 2,735,088 by D. J. Kinzer, issued Feb. 14, 1956. It is also known to use capacitively coupled indicators for external circuit wires such as is taught in U.S. Pat. No. 2,036,223, issued Apr. 7, 1936 to H. Lapple. It is also known to use neon lamps and condensers for certain purposes in conjunction with fuses and fuse holders. Such uses are taught in U.S. Pat. No. 3,229,065 issued Jan. 11, 1966 to E. Borys, and U.S. Pat. No. 2,545,760 issued Mar. 20, 1951 to P. B. Blanchard. It is also known to use translucent fuse barrels through which can be seen an electroluminescent effect which occurs under certain electrical conditions. Such a use is taught in U.S. Pat. No. 3,513,427 issued May 19, 1970 to K. W. Prosser et al. It would be advantageous if a submersible fuse of the type found in underground transmission systems could be provided with an indicating means for indicating the status of the fuse, that is whether it is blown or conducting. Furthermore, it would be further advantageous if the mode of coupling the indicator to the fuse was indirect (i.e. capacitive) so that the natural capacitive effect of the main body of the insulating enclosure could be utilized.